Adjustable pliers



April 15, 1952 H. H. MANNING 2,592,927

ADJUSTABLE PLIERS Filed Aug. 4, 1949 Jmaentor attorney Patented Apr. 15, 1952 2,592,927 ADJUSTABLE Pmnns Howard H. Manning, Meadville, Pa., assignor to Champion De Arment Tool Company, Mead= ville, Pa., a corporation of Pennsylvania Application August 4, 1949, Serial No. 108,578

2 Claims.

This invention relates to hand tools, such as pliers, having members pivoted by tongue and groove joint elements. In a preferred form there members which are selectively usable for different jaw openings. Such tools, under working conditions, are subject to heavy stresses. This invention is intended to improve the working strength by terminating the joint elements short of the edge subject to tension stress. This provides a higher effective strength under Working conditions without increasing the weight. Further objects and advantages appear in the specflcation and claims.

In the drawing, Fig. 1 is a side view of a pair of pliers; Fig. 2 is a section on line 22 of Fig. 1; Fig. 3 is a fragmentary view of a section having higher working strength; Fig. 4. is a fragmentary view of another section having higher working strength. and Fig. is a section on line 5-5 of Fig. 4.

The invention is shown applied to a tool of the construction illustrated in my Patent 1,950,362. As there shown the tool comprises pivoted members I and 2 respectively provided with jaws 3 and 4 offset to one side of a bolt 5 extending through an opening 6 in the member 2, and a slot 1 in the member I. On the opposite side of the bolt the members are provided with handles 8 and 9. On the member 2 is an arcuate rib Iii receivable in anyone of a plurality of arcuate grooves II in the member I, the grooves being defined by ribs I la some of Which are in the range of the slot I. The width of the jaw opening is adjusted by sliding the bolt 5 along the slot a until the rib It comes opposite the desired groove I I. From one aspect .the rib It and groove ii are tongue and groove joint elements. The parts so far described are shown in greater detail in my aforesaid patent.

Under. working conditions the reaction forces on the'jaw 3 stress the edge I2 of the member I in compression and the edge I3 of the member I in tension. Because the tension edge I3 is interrupted by the grooves II, there are points of stress concentration which are greatest at the points I4 where the corners of grooves II intersect the tension edge I3. At the points I4 there is an abrupt change in the width of the tension edge I3. While the stress concentration is objectionable under static loads, it is particularly objectionable under the working loads encountered in pliers which are of the nature of suddenly applied or impact loads.

It is found that the working strength of the pliers can be substantially doubled if the ends I5 of the ribs Ila adjacent the tension edge I3 are cut off so as to make the tension edge continuous. By doing this the ribs I la defining the grooves Ii terminate short of the tension edge and there are no points of stress concentration at which failure can start. In other words, by removing some of the metal heretofore considered necessary, the working strength of the pliers is increased. Since the Weakest section of the pliers is that opposite the slot I, it is particularly desirable that the ends I5 of the ribs Ila be out off in this region. In a preferred form shown in Fig. 4 the tension edge I3 comprises a longitudinal rib I 5 having its upper surface at or slightly below the base of the grooves I I. Since the plier members are usually made of forgings it is more convenient to have the upper surface of the rib It below the base of the grooves II. In both cases the highly stressed tension edge I3 is a smooth continuous edge free from points of stress concentration at which fracture can start under working stresses. Whether the elimination of the points of stress concentration is obtained by cutting off the ends I5 of the ribs Ia, or by adding a continuous rib I6, is a matter of design. In either case the strength under impact loads which more closely approximate the working loads in a plier is increased nearly double while the strength under static loads remains essentially th same as the construction illustrated in Fig. 1.

What I claim as new is:

1. In a tool having a pair of crossed members, one having a slot and the other having a. pin in the slot, work engaging surfaces on the members offset to one side of the slot, and tongue and groove elements on adjacent faces of the crossed members comprising an arcuate rib on the pin carrying member concentric with the pin and a plurality of arcuate ribs on the slotted member defining a plurality of spaced open ended grooves in any one of which the rib on the pin carrying member is receivable to provide a pivotal connection between the members, at least all of the arcuate ribs on the slotted member in the range of the slot terminating short of the edge of the slotted member on the side from which the work engaging surfaces are offset.

2. In a tool havin a pair of crossed members. one having a slot and the other having a pin in the slot, work engaging surfaces on the members offset to one side of the slot, tongue and groove elements on adjacent faces of the crossed members comprising an arcuate rib on the pin carry- 3 ing member concentric with the pin and a plurality of arcua-te ribs on the slotted member defining a plurality of spaced arcuate open ended grooves in the slotted member in any one of which the rib on the pin carrying member is receivable to provide a. pivotal connection between the members, and a longitudinal rib on the edge of the slotted member' toward the=wor1e engaging surfaces-having its upper surfaee 'at or below the bottom of the arcuate ribs defining the grooves on the slotted member. and the ends 01' the arcuate ribs on the slotted member terminating short of the longitudinal rib. HOWARD H.

4 REFERENCES CITED The following references are of record in the file of this patent:

5 UNITED STATES PATENTS Number Name Date 397,389 Richards Feb. 5, 1819 1 .8 1;3 ,8;19' Jackson Feb.-2, 1932 15950362 Manning --Ma r. 6, 1934 10 FOREIGN PATENTS Nfirnber Country Date 119,151 Great Britain Sept. 26, 1918 99,868 Sweden Sept. 17, 1940 

